The invention relates to machines for brewing coffee, tea or other hot beverages, and more particularly to improvements in machines of the type wherein a liquid storing and dispensing container is mounted adjacent a hollow base or housing for confinement of an electric heater and of conduits which connect the inlet and the outlet of the heater with the container.
It is already known to provide a coffee maker or an analogous machine with a container which is mounted on top of a hollow base and confines a riser for hot liquid. The riser serves to receive hot liquid from the outlet of the heater and to admit the liquid into a filter holder wherein the liquid contacts a metered quantity of flavoring agent, such as pulverulent cocoa or chocolate, tea leaves or ground coffee beans. As a rule, the electric heater is a so-called through flow heater wherein a pipe defines an elongated path for the flow of liquid from the inlet to the outlet. The inlet receives fresh liquid from a first nipple of the container by way of a first conduit, and the outlet supplies heated liquid to a second nipple of the container by way of a second conduit. The second nipple admits hot liquid into the lower end of the riser in the container. Examples of such machines are coffee makers known as "BREWMASTER JR.", "BREWMASTER" and "BREWMASTER II" which are produced and distributed by the assignee of the present application.
A check valve is normally installed in the path of flow of fresh liquid from the container to the inlet of the electric heater to prevent return flow of hot liquid and/or steam into the container by way of the first nipple, for example, when the pressure of heated liquid in the heater rises to or exceeds a given value The base of the machine can be equipped with a warming plate for a vessel (e.g., a coffee pot) which is located beneath the filter holder and serves to receive the freshly brewed beverage.
The check valve is open in normal operation of the machine and permits fresh liquid to flow from the container by way of the first nipple, thereupon through the heater, into and upwardly through the riser and thence into the filter holder. A drawback of presently known machines which employ such check valves is that the valves contribute excessively to overall cost of the machines. As a rule, the check valve is a separately produced part which is installed in the path for the flow of fresh liquid from the container into the inlet of the electric heater. The separately produced valve is installed in the conduit between the first nipple of the container and the inlet of the heater or upstream of such conduit. The valve has a cage for a spherical valving element, and the cage must be installed in or ahead of the aforementioned conduit between the container and the inlet of the electric heater in a time-consuming operation.